Fe-based nanocrystalline FINEMET cores for induction accelerators

Abstract Pulse power modulators used for high repetition rate linear induction accelerators are generally composed of main switches using thyratrons, step-up pulse transformers, multistage magnetic pulse compression circuits and pulse forming lines. Fe-based amorphous cores are normally used for saturable reactors in linear induction accelerators, because the volume of the saturable reactor using Fe-based cores is small due to its high effective induction swing. However, there is a great demand to reduce the core loss in order to improve the efficiency of pulse power modulators. Recently, a new Fe-based nanocrystalline soft magnetic materials, FINEMET, that has both high saturation flux density and low core loss was developed. The dynamic magnetic characteristics of an insulated FINEMET core were measured using a high voltage pulse excitation circuit, and the total core volume and the total core loss for saturable reactors in a 2-stage magnetic pulse compression circuit were calculated. As the result, by using the FINEMET cores for saturable reactors in a magnetic pulse compression circuit, the total core loss becomes 68%, and the total core volume becomes 133%, of the conventional Fe-based amorphous cores.